Updated hot melt guidance reflects current roofing standards

By Alex Tolle. 

The revised code provides practical guidance on the design, installation and verification of hot melt waterproofing systems. 

The Liquid Roofing and Waterproofing Association (LRWA) has published Version 2.2 of its Hot Melt Code of Practice, dated August 2026. Updated to reflect BS 6229:2025, the code offers roofing contractors, manufacturers and specifiers a current reference for hot melt waterproofing across flat roofs, podiums, terraces, balconies and walkways.  

The guidance covers system selection, specification, design, installation and maintenance. It places particular emphasis on creating the correct falls during the design and construction stages. Inadequate falls can allow standing water to form, adding structural loads that the roof may not have been designed to accommodate and accelerating material deterioration.  

The revised code also provides updated guidance on zero falls and absolute zero falls, as well as applications involving inverted warm roofs and blue roofs. These updates can support roofing professionals when pricing work, briefing site teams or responding to client queries.  

Substrate preparation receives significant attention. The code addresses concrete curing times, peel bond testing procedures and the treatment of curing compounds that may be compatible or incompatible with hot melt waterproofing systems. It also confirms electronic integrity testing (EIT) as the recognised method for verifying waterproofing integrity on site, replacing traditional flood testing. 

“This update ensures the LRWA Hot Melt Code of Practice reflects the requirements of BS 6229:2025 and continues to give the industry a definitive, authoritative reference for Hot Melt waterproofing systems,” said Mike Bradbury, LRWA technical guidance manager. “Falls and drainage remain critical to the long-term performance of a roof, and this edition reinforces that guidance throughout.”  

Developed by the LRWA Technical Advisory Group with input from manufacturer, contractor and specifier members, the complete code is available to download free of charge.